Dopamine-Beta-hydroxylase (DBH) is an enzyme which is required for the biosynthesis of norepinephrine and epinephrine. It is known that neuronal activity can influence the rate of synthesis of DBH by transsynaptic induction. We are attempting to devise a cell free system in which the synthesis of DBH can be investigated. We are usng RNA from bovine adrenal medulla and rat superior cervical ganglion as templates for protein synthesis. A sensitive and specific radioimmunoassay has been developed for the detection of the DBH.